Fedify has just laid out a comprehensive implementation plan for this fep:
https://github.com/fedify-dev/fedify/issues/288#issuecomment-3971459585
The core idea is replacing HTTP(S) URIs with server-independent identifiers:
ap://URIs that use a Decentralized Identifier (DID) as the authority component, rather than a domain name. An object identified asap://did:key:z6Mk…/actorcan live on multiple servers simultaneously and survives any single server disappearing.
w3.org
Decentralized Identifiers (DIDs) v1.0
Decentralized identifiers (DIDs) are a new type of identifier that enables verifiable, decentralized digital identity. A DID refers to any subject (e.g., a person, organization, thing, data model, abstract entity, etc.) as determined by the controller of the DID. In contrast to typical, federated identifiers, DIDs have been designed so that they may be decoupled from centralized registries, identity providers, and certificate authorities. Specifically, while other parties might be used to help enable the discovery of information related to a DID, the design enables the controller of a DID to prove control over it without requiring permission from any other party. DIDs are URIs that associate a DID subject with a DID document allowing trustable interactions associated with that subject.